1. Field of the Invention
This invention relates to a tamper-evident closure cap and corresponding container and, in particular, to a cap having a removable skirt with projections that correspond to projections on said container. When the cap is turned onto said container, the projections override one another and when the cap is turned off said container, the projections interlock with one another.
2. Description of the Prior Art
It is known to have a closure cap with a removable skirt connected to a remainder of said cap by severable tabs. However, with one type of known tamper-evident closure cap, a neck of a conainer has a circumferential ridge thereon and an interior surface of the skirt has a similar circumferential ridge. As the cap is turned onto the container, the ridge of the cap is designed to override the ridge of the container. As the cap is turned off said container, as long as the relative size of the cap and container are within acceptable tolerances, the ridge of the cap cannot override the ridge of the container and the tabs are severed, thereby removing the skirt from a remainder of said cap. In another known type of tamper-evident closure cap, the skirt has a circumferential flange that is hinged to a bottom edge of said skirt. A corresponding container has a circumferential ridge surrounding a neck thereof. As the cap is turned onto the container, the flange is compressed against an interior surface of the skirt so that it will override the ridge on the container. As the cap is turned off the container, as long as the relative size of the cap and container are within acceptable tolerances, the flange pivots about the hinged portion so that the flange cannot override the ridge on the container and the skirt is severed from a remainder of said cap. These known prior art tamper-evident closure caps suffer from a serious disadvantage in that the caps and containers must be manufactured within a very narrow tolerance in order for the tamper-evident parts of the cap to work properly on a container. It can be appreciated that the cap must be large enough so that the skirt will slide over the ridge on the container when the cap is turned onto the container but will not slide over said ridge when the cap is turned off the container. Often, the caps and containers are manufactured by different manufacturers. The close tolerances required cannot always be achieved and the caps do not always work properly. If the circumferential ridge on the skirt or on the cap is oversized or undersized, the tamper-evident features of the cap will either not work at all or the skirt will become severed from a remainder of the cap while the cap is being turned onto said container. Also, as the skirt of the cap must override the circumferential ridge on the container when the cap is being turned onto said container, tabs interconnecting the skirt with a remainder of the cap must be designed to be quite strong so that they will not sever prematurely. Since the tabs are strong, it can be difficult to turn the cap off the container as it is difficult to sever the tabs. The problem with tolerances is particularly important where caps and containers of relatively large diameters are utilized or where both the cap and container are constructed of plastic. With large diameter caps, a small percentage variance in the size of the cap or container can result in a very large size discrepancy so that the ridge on the cap simply overrides the ridge in the container when the cap is removed from the container. Similary, if the container and cap are both made of flexible and resilient materials, the ridges of the cap and container could also override one another. When this occurs, no evidence of tampering will exist when the cap is removed from the container and subsequently installed.